Chalice of harmony
=> you think i am dumb ! No... This item is very very cheap and gives you MR and the most efficient mana regeneration in the game. Thus, you can spam your skills at lane and control perfectly top.

Hexdrinker
Good overall item. Could be replaced by Thornmail if there is too many AD.

Aegis of the legion
Replace Doran's Shield by this ! good overall item also

Trinity force
Replace Chalice of Harmony by this. No need to say more on this, you should probably now everything about it.

Skill Sequence

- First max Hiten Style because it is your main regeneration during laning phasis. This is also, combine with Wit's End, a wonderful damage oupout when you auto attacks.
- Then max Equilibrium Strike : good damage output and slow/stun. 1 point at lvl one to avoid diving or keeping your *** up if someone is chasing you.
- FinallyBladesurge : 1 pt at lvl 4 only to help you farming/chasing enemies. Don't forget that you can use it to escape from a fight by targeting minions !

9 x Greater Seal of Resilience brings a nice armor bonus at the begining that helps your laning. You don't have to pick mana regeneration because of Chalice of Harmony in this build

Summoner Spells

Flash

Best spell in the game.
- Deadly when uses offensivly
- Best escape

Ignite

Shutdown some heroes like Vlad, Swain, Tryndamere... great damage also

Exhaust

Good pick also (pick enhanced exhaust with it)
Shutdown AD carries : this is the what you needed if theer is more than 2 or 3 AD carries in the game !

Pros / Cons

Pros

- God mid/late game
- Almost imune to magic damage
- Lot's of true damage, works on everyone
- Perfect in current metagame

Cons

- Require mass farm
- ... that's all ?

Farming, Harass and lane control

Farming is the most important thing with this build.

Early game
Last hitting only. Do not push your lane at all or you can be traped by the jungler or stuck into brushes. At lvl 4, Bladesurge helps you to last hitting but keep your mana up.
Lvl 6 : you ultimate Transcendent Blades is a blessing : you can push so hard by killing an entire wave of minions with it and get a nice life regeneration.
Irelia is pretty squishy early game so be careful and play safe.

Mid game
Keep farming a lot and add bleu/red buffs in your farming
At this point, you should be capable to handle your lane without any problem. You can poke really hard with your Q/E/W combo.

Combos

Early game
You should not be very agressive... focus on farming.

Mid late game
If you opponent approach you too much use E->W and poke/chase with Q.